Research Interests: My overall scientific interest is to better understand the cycling of natural organic matter in the earth’s surface, mainly in aquatic environments such as oceans, estuaries, rivers, groundwater, and lakes. A key objective of my research is to elucidate the role that organic matter plays on the global biogeochemical cycles of major elements (e.g., carbon, oxygen, nitrogen). Specific areas of my on-going research include: 1) Understanding the processes controlling organic matter cycling in river-dominated ocean margins, including deltas and estuaries. 2) Investigating the factors that control the generation and export of organic matter from the surface ocean and its transport, cycling and preservation in marine sediments. 3) Reconstructing the sources and compositions of organic matter in sediments over glacial - interglacial scales. 4) Assessing the role of natural organic matter on the behavior of particle reactive contaminants in coastal environments. 5) Developing and applying novel analytical techniques for the study of organic matter in the ocean. Current Research: Sources, transport and fate of terrigenous organic matter in river dominated margins, including the Gulf of Papua (Papua New Guinea),Gulf of Mexico,Arctic,Southeast U.S. Fluxes and transformations of organic matter in the water column and sediments from upwelling margins such as theCariacoBasin. Climatic and oceanographic reconstructions of Holocene conditions in tropical and temperate ocean margins using organic biomarkers.